I was born and raised in the U.S. South, and I've always said 'nyew' which rhymes with the way I would say 'ewe'. It's very true that whereever you go in the USA, you will hear varied pronunciations, and determining what is standard American is very difficult. I have lived in Tennerssee in what I called 'Nashvul' much to the amusement of my nothern friends who said 'Nash Ville.' I have lived not too far from 'Nyorlins' which many people pronounce 'Noo Orleens'. I lived near Chicago for a while where restaurants offered not 'pi cahn' but 'pee can' pie. I lived in California where most people say 'Loss Anjelus', but some say 'Loss Anjuleez' and old timers say 'Loss Angulus'. Now I live in the Northwest which is said to be the place with the closest to the Standard American accent. Maybe, but I think it's because you hear all of the above here.
Jude
